UCL SUSY and other BSM physics with CMS G. Bruno on behalf of the CMS Collaboration Center for Cosmology, Phenomenology and Particle Physics (CP3) Université

UCL

SUSY and other BSM physics with CMS

G. Bruno on behalf of the CMS Collaboration

Center for Cosmology, Phenomenology and Particle Physics (CP3)

Université catholique de Louvain (UCL), Louvain-la-Neuve, Belgium

LHC Days in Split Conference30/9/2014

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The Standard Model puzzles

• Higgs boson discovery has completed the SM • Key unanswered questions:

o Dark mattero Matter-antimatter asymmetryo Neutrino masseso Gravity and “dark energy” o Unification of forceso Deeper origin of electroweak symmetry breakingo Deeper origin of fermion mass hierarchies, flavor

mixing, and CP violation• BSM Physics that would address these questions

is in many cases expected at the TeV scale

Split2014 – BSM in CMS

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BSM physics ideas


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How to search for BSM physics at the LHC

• Scalar sectoro Precise measurements of Higgs couplings and properties o Search for an extended scalar sector

• Precise measurement of SM observableso Few, yet notable, competitive examples

• Final states with top quarkso Strong and ew couplings o Rare decayso Top squark, vector-like top partners, tt resonances

• Other direct searches for new physicso Inclusive squarks and gluino (and neutralino) searcheso Compressed SUSY spectrao R-parity violating susy searcheso New vector bosons o mono X searches (heavy, strongly interacting states are out of reach)o Long-lived particles


Talks by:J.-P. SauvanA. NikitenkoF. Pandolfi

Talks by C. Grab and E. Gallo

Talk by J. Cuevas Maestro

Talk by R. Bartek

Talk by M. Kazana

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Supersymmetry


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SUSY searches

• High cross section – gluinos,1st and 2nd generation squarks

o Multijets + MET w/wo b-jets, leptons, photons


• Medium cross section – stop and sbottom

o Multi-jets + MET + b-tags w/w.o. leptons

o Dedicated searches

• Low cross section – Charginos, neutralinos, sleptons:

o 0-4 leptons + METw/w.o. b-tags, jets, W’s, Z’s, h’s

Highly motivated theoretical framework

o Lays the bases for unification of forces

o Provides a dark matter candidate

o Can stabilize the Higgs mass

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All-hadronic inclusive search

• Gluinos,1st,2nd gen. squarks• 36 signal regions in bins of

o Jet multiplicity (≥3)o HT (≥500 GeV)o HTmiss (≥200 GeV)

• Limits in Simplified Model Space (SMS)


1402.4770

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The search for (natural) stops


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Stop search for moderate mass differences

Combination of 2 analyses (SUS-14-011):

• Inclusive search with ETmiss, b-jets w/wo

leptons (SUS-13-004)o Uses razor variables in several disjoint

boxes

• Exclusive analysis targeting the final state (1308.1586)

o BDT selection on events with 1 lepton, ≥4 jets (≥1btagged) and Et

miss

• Limits depend on stop decay BRso Most stringent for BR()=1o Also conservative BR-independent result


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Stop search: filling the gaps

• Monojet dedicated analysis (SUS-13-009)o ISR can induce high ET

miss

and relatively soft charm jetso Et

miss>250 GeV;

o pT(j1)>110 GeV


• Stops from gluinos (1311.4937, 1305.2390)o 0/1 leptons, multijets, bjets and ET

miss

• Stop1 from stop2 (1405.3886)o 1-3 leptons, multi-(b)jets and ET

miss optimized for

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Ewkino searches

• Inclusive multileptons, ETmiss

w/wo jets search (1405.7570)

o 2/3/4 leptons + ETmiss

o 2 SS leptons + Etmiss

o W(jj)/Z(jj)+Z(ll) + Etmiss

o W(l)H + ETmiss

o Interpretation in several specific SMS


• Search targeting hh / hZ / hW + ET

miss

(1409.3168)o o Interpretation in

scenarios with higgsino or gauginos

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M(l+l-) kinematic edge search

• Generic search for a kinematic endpoint in the invariant mass distribution of OS-SF lepton pairs (e or μ) in events with ET

miss and jets o E.g. o Two search regions: central (2l in |η|<1.4) and forward (1l in1.6<|η|<2.4)

• Background estimated from OS-OF lepton pairs

• Fit the observed distribution with B-only and S+B modelso Also cut & count analysis in signal region 20<M()<70 GeV


OS-SF OS-OFCut&Count

SUS-12-019

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DARK MATTER


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Dark Matter (DM) searches

• DM-nucleon scattering (LUX, CDMS, XENON, …)

• DM annihilation or decay (Fermi, PAMELA, AMS, IceCube, …)

• DM production at colliders

o Particularly competitive at low DM masses

o DM produced in cascade decays from heavier particles: Supersymmetry, Higgs portal

o Direct DM production• Detectable if accompanied by additional objects (e.g. ISR)• Interpretation in terms of Effective Field Theories


Key parameters:

• DM mass mDM• Mediator mass M• Interaction type (scalar,

vector, axial-vector, tensor)• Couplings

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Mono-X searches• Mono-jet (1408.3583)

o >110 GeV ||<2.4o >250 GeV o strongest limits on vector and

axial-vector interactionso Also on ADD G, unparticles

• Mono- (EXO-12-047)o >145 GeV ||<1.44o >145 GeV

• Mono-o Semileptonic (B2G-14-004) and

dileptonic analyses (B2G-13-004)o Strongest limit on scalar

interaction (strength )

• Mono- (B2G-12-022)o Requires FCNC or Baryon number

/ R-parity violationo Limits set on scalar and vector

boson DM produced via FCNC


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Limits on DM


MONO-JET: vector () and scalar (gg) interaction

MONO-JET: axial-vector () interaction

MONO-tt: scalar interaction ()

Invisible Higgs: scalar, fermion and vector DM

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Mono-W (DM-DM-W production)

• If u and d quarks couples differently to DM, interference can make mono-W the dominant process

o is the relevant parameter

• Standard lepton(e or μ) + ETmiss search in the MT

spectrum (1408.2745)o Sets limits on SSM W’, CI, UED W(n)

KK, as well as model-independent ones


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EXTRA-DIMENSIONS, COMPOSITENESS and new BOSONS


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Theoretical context• Extra dimensions

o Address hierarchy problem by extending space-time dimensions (4+δ in ADD variant)

• (δ dimensions compactified over multidim torus of radius )• RS variant: 1 ED and warped space-time• Gravity propagates in all dimensions and appears weak in 4 dim space time

o KK excitations of all known SM particles• Can provide dark matter candidates• ADD: non-resonant enhancement• RS: distinct resonant production

• Compositenesso Known fermions would be composed of more fundamental constituents

interacting via a new strong gauge interaction• At energies smaller than the new interaction scale Λ, it manifests as a contact

interaction giving event rate enhancements

• Most sensitive searches: di-fermions and mono-X


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Dilepton searches

• Narrow resonances (EXO-12-061)o Shape analysis in the full

unbinned di-μ and di-e inv. mass spectra

• Enhancement in di-lepton event rates at high mass (EXO-12-027, EXO-12-031, EXO-12-020)o Count events beyond

mass threshold


EXO-12-027

EXO-12-061

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Dilepton searches - limits

• Limits from peak search w.r.t. previous 5+5 fb-1 paper (1212.6175):

o Z’SSM : 2.59 TeV 2.96 TeVo KK graviton (): 2.39 TeV t.b.u.

• Limits on MSvs nED in the ADD ED

• Limits in the LLIM variant of CIo For both destructive and constructive

interference with DY productiono Limits on HnCM from “mono-W” search


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FINAL STATES WITH TOP QUARKS


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ttbar invariant mass distribution

• Combines semi-leptonic and all-hadronic analyses

o All-hadronic: 2 back-to-back top-tagged CA8 jets with pT>400 GeV

o Semileptonic: has both resolved (1l,≥4j) and boosted (1l wo isolation, ≥2j) event categories (transition at TeV )

• Subjet identification in boosted category• Background control with 0 btag selection

• Results from simultaneous fit to the different distributions


1309.2030

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Rare top decays

• FCNC (1312.4194): o SM decay BR of order (10-14) occurring via loop diagrams.o RPV susy, warped ED and others predict enhancements up to 10-4 -

10-5 with large model parameter dependenceo Search for with leptonic (e or μ) decay for W and Z o BR( excluded at 95% CL

• BNV (1310.1618): ()o Baryon Number (BN) is a conserved quantity in the SMo BN violation necessary condition for matter-antimatter asymmetry in

the Universe.• Predicted in RPV susy, and grand unification models

o Recent theory paper has noted that the above decay could occur at relatively high rates, preserving proton stability

o search for in electron and muon channelo BR( excluded at 95% CL (and similar for muon channel)


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NEUTRINOS


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Search for RH heavy neutrino and W

• Search guided by Left-right symmetric SM extensions

o Predicts heavy RH W/Z and Majorana neutrinos, explaining neutrino masses through see-saw

o Signature with SF leptons:

• Shape analysis in the lljj invariant mass spectrum

o No distinction between OS and SS leptons

• First limits on WR beyond the th. lower limit MWR >2.5 TeV (from KL-KS mass diff.)

o 2.8 σ local excess in electron channel (only 1 SS pair out of 14 events and no deviation in muon channel)


1407.3683

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Conclusions

• Huge spectrum of BSM physics searches performed by CMS

• Overview and personal selection, with some physics guidance, presented in this talk

• Ground prepared for the RUNII data analysis


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BACK-UP


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Conclusions


Documents

UCL SUSY and other BSM physics with CMS G. Bruno on behalf of the CMS Collaboration Center for Cosmology, Phenomenology and Particle Physics (CP3) Université